1. Field of the Invention
The present invention relates to a novel and improved coating composition and process for applying a water-based vinyl acetate/acrylic polymer blend emulsion copolymer based coating or paint to polyvinyl chloride or styrenic elastomeric polymer surfaces, particularly to toy articles. Because the coating composition uses water based solvents, it can be applied as a coating or paint for toy articles which can be safely used by children.
2. Description of the Related Art
Generally, the technology surrounding the manufacture of toys centers on creation of a toy item such as doll, miniaturized application of conventional clothes, manufacture of a doll body using plush or other sculptural techniques, and the simulation of the hair with sculptural elements, fibers, or other techniques. In addition to dolls, hand painted clothing and fabrics have become increasingly popular among child and adult consumers over the past several years. This popularity has spurred the development of craft kits that are designed to allow the consumer to make his or her own hand painted clothing or fabrics. In the case of dolls, soft elastomeric rubber materials such as styrene-butadiene rubber (SBR) and styrene-butadiene-styrene (SBS) block copolymer (Kraton) elastomers are used extensively in the production of doll heads because of their realistic look and feel. Polyvinyl Chloride has been one of the polymeric materials of choice for miniaturized fabrics because of its availability, relative inexpensiveness, flexibility, and strength as paint receptive sheet materials for clothing and the like. However, it has proven difficult to provide a paint composition that, when applied to fabrics and elastomeric sufaces in toy articles, possesses desirable aesthetic and wear properties while also being capable of withstanding repeated physical abuse endemic to toys without losing these properties.
One of the desirable aesthetic properties sought after by toy consumers in such paints is a high degree of gloss. In addition, the paint should have sufficient flexibility so that cracking does not occur as the toy article or fabric moves during cleaning or wear; that is the painted surface should be washable. Paints which allow the creation of three-dimensional lines on a fabric or a flexible skin surface of an article, and which will hold this configuration after drying, are also highly desirable. Another desirable property is the ability of a paint to provide a “glitter” effect when exposed to light. Further, it is advantageous that any such paint be relatively non-toxic and economical to produce.
Regardless of the type of paint used on a toy doll article, it has remained imperative that such materials be safe for young children. Safety requirements have evolved through the years as safety concerns have grown. Generally, safety mandates that any material compositions used in a toy be odorless, nonirritating to the skin or eyes or the like, and be nontoxic if ingested. Additional requirements have been expected of materials used to coat or paint toy articles in that they must be non-peeling, requiring that the coating or paint tenaciously adhere to the toy item to avoid flaking or peeling and possible consumption by a child user. Accordingly, such paints should be resistant to oxidation and flaking, particularly as applied to elastomeric rubber surfaces of soft doll faces. And further the paint should be able to withstand the stretching and other physical abuse of a child so that the appearance of the painted surface is maintained. And above all the paint or coating composition must avoid the use of undesirable volatile organic solvents the residual presence of which can be dangerous due to the toxic effect of certain aromatic and chlorinated hydrocarbon solvents. In view of the environmental, health and safety concerns in the use of highly toxic organic solvents, less controversial solvents such as water are used to provide toy paint or coating compositions, as in the case of the instant invention.
As indicated above, the class of the styrenic elastomeric materials commonly used to mold doll faces and other toy articles are A-B-A type block polymers such as styrene-butadiene-butylene-styrene or styrene-butadiene-styrene, manufactured by Shell and sold under the trademark Kraton. The molded elastomeric doll faces tend to be dull and unattractive and so are finished by application of a skin coating or paint to provide a good facial appearance to this facial piece. Fabric items made from polyvinyl chloride also require a paint which will be capable of maintaining a high degree of gloss during use, can hold a dimensional line after drying, and/or can be brushed out flat. It has now been found that a coating composition comprising a certain water-based vinyl acetate emulsion copolymer/acrylic polymer latex blend and polyvinyl alchol has particular advantages in forming tenaciously bonded adhesive coatings on styrenic resin and polyvinyl chloride.
Vinyl acetate homopolymer and copolymer emulsions are well known in latex paint formulations. It has further been found that vinyl acetate-ethylene emulsions can be blended with acrylic polymers to achieve superior exterior paint formulations. In fact, data exists to prove that a blend ratio of up to 49% vinyl acetate-ethylene emulsions with as much as 51% acrylic polymers produces coatings with properties essentially comparable to those of coating based on 100% acrylics. The instant compositional invention exploits this finding to achieve a new coating formulations which are particularly effective on polyvinyl and elastomeric sufaces of toy articles.
The present application provides an aqueous-base coating composition containing a vinyl acetate homopolymer or copolymer emulsion/acrylic polymer latex blend binder and a polyvinyl resin (eg. polyvinyl alcohol) film forming binder composition which is effective in retaining an applied film of the coating composition after its application to the surface of an elastomeric or polyvinyl chloride object and prior to the thermal or cure bonding of the composition to the object's surface.